OpenEnergyMonitor Community

emonTH Alternative Antenna

Hi OEM Community,

Are there any possible antennas that can be easily installed for emonTH?

The default signal strength that we are receiving from the emonTH is not ideal after penetrating through walls / doors etc.

Thank you!

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Have you brought the whip antenna out of the case and extended it in a straight line? If it’s coiled inside, that is the first thing to do.

The next easiest way to improve signal strength is to provide the antenna you have with a ground plane.
There was a big discussion a little while ago - Improving RF signal strength emonTH emonTX
You can have the ground plane at either or both ends of the link.

There is provision for a socket (SMA - as the emonTx) on the emonTH pcb, but the case will need serious modification. With a socket, an external Yagi (directional) antenna would be possible.

Hiya, I moved my emonPi to an outbuilding and needed to boost the EmonTH signals.

I found emonTH Range testing. It mentioned a “ground plane” which I tried with some success on the emonPi but I couldn’t work out how best to do it for the emonTH (I tried various orientations of the ground plane and the emonTH but couldn’t find a combination that made much difference).

I also found Improving RF Signal. As a result I screwed a 165mm length piece of wire (a single strand from a dead network cable) as an extra aerial to the GND (3rd screw from the left) of the emonTH.

That made a dipole. A ground plane antenna works in exactly the same way. There is the ‘active’ element on one side, and the ground plane forms an “image” element on the opposite side.

You have a physical element instead of the image.

Great, thanks for the explanation!

Hi @Robert.Wall and @christian , thank you both for the kind sharing.

We do not have an actual ground plane but we did create our own aluminium ground plane and placed our emonTH with the whip antenna extended out of the case in a straight line. The ground plane did provide a significant increase in signal strength received.

However, installation of the ground plane is not feasible for our use case. And as such, the emonTH with the whip antenna extended out of the case does not provide a strong enough signal strength for us.

Thus, we would like to understand if there are alternative whip/screw-on antenna that we can easily install onto the emonTH to increase our signal strength.

Thank you!

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See my first reply:

and look at the photographs of the emonTx. According to the BoM, the antenna socket is Supplier: Molex / Waldom; Part No: 73251-2120

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